ATHENS, Greece - Greece's coalition government faces its toughest test so far when lawmakers vote later on new austerity measures demanded to keep the country afloat.

The €13.5 billion ($17.3 billion) package is expected to scrape through late Wednesday, following a one-day debate. But potential defections could severely weaken the conservative-led coalition formed in June with the intention of keeping Greece in the euro.

Without approving the package of spending cuts and tax increases, Greece will potentially lose its bailout funds, default on its mountain of debt and probably leave the euro.

But approval will compound the misery of a population hit by successive income cuts over three years, a deep recession and record-high unemployment.